1. Field of the Invention
The present invention generally relates to a manually-operated suction device, and in particular to a suction device that attaches/separates an article, such as a mobile phone and a personal digital assistant (PDA), to/from a smooth flat surface by rotating a rotatable cap to cause/release deformation of a suction cup, which induces a suction force between the cup and the surface due to pressure difference.
2. The Related Art
It is common to retain a mobile phone or a PDA on a designated sites, such as inside a car or on a office table, by a mobile phone holder, to allow a mobile phone user to take an incoming call or make an outgoing call without hand holding the phone, whereby the user is allowed to proceed with what is being done without interference caused by operating the phone.
A conventional mobile phone holder employs fasteners, such as bolts, to fix the holder to the designated site. Using bolts to fix the mobile phone holder usually causes damage to the surface to which the holder is attached. Further, the holder is not allowed to readily move to other sites. Another way to fix the mobile phone holder to a fixed surface is employing adhesives to adhesively attach the holder to the surface. Similarly, fixing the holder with adhesives does not allow the holder to be readily moved. In addition, an adhesive mark is often left on the fixed surface once the holder is removed from the fixed surface. Such a mark is difficult to clean off.
Another conventional device for fixing a mobile phone holder to a fixed surface is a suction cup, which comprises a deformable cup that deforms to induce pressure difference by which a suction force is caused to fix the holder. The suction force is generally dependent upon the projected area of the cup. A small cup usually leads to a small and insufficient suction force that cannot firmly and stably supports a mobile phone or other objects. However, a large cup requires a large footprint on the fixed surface, which causes inconvenience in operating the suction cup. In addition, the large cup often deteriorates overall surface aesthetics, due to occupation of large space.
Thus, it is desired to have a suction device that overcomes the problems discussed above.